CN110579041A - A thermoelectric decoupling system and operation method based on absorption heat pump - Google Patents

Abstract

The invention relates to a thermoelectric decoupling system based on an absorption heat pump, comprising an absorption heat pump comprising a generator, a condenser, an absorber, a solution pump, a solution heat exchanger and a solution valve. Due to the cancellation of steam extraction for heat supply, the present invention can realize thermoelectric decoupling and solve the problem of poor flexibility of cogeneration units in my country. The present invention uses the heat of the main steam of the boiler to supply heat to the outside, and the heat load of the boiler is relatively high; it can be adjusted into the absorption type The main steam flow in the heat pump realizes the adjustment of the heat absorbed by the heating surface of the boiler, which is conducive to the safe and stable operation of the boiler; injects part of the steam generated in the generator to the ejector, and increases the pressure to provide driving force for the generator. A part of high-grade steam is replaced by low-grade steam to reduce heating costs; the open absorption heat pump absorbs the exhaust heat of steam turbine to supply external heat, which improves COP.

Description

A thermoelectric decoupling system and operation method based on absorption heat pump

technical field

The invention belongs to the technical field of cogeneration of heat and power, in particular to a thermoelectric decoupling system and an operation method based on an absorption heat pump.

Background technique

Combined heat and power generation is a technology that comprehensively utilizes energy, which realizes energy saving, improves environmental conditions, and improves residents' living standards. In the process of urbanization in my country, it plays an active role in solving the growing power supply and urban heating. . With the rapid development of wind power, photovoltaics, and nuclear power and the country's increased consumption of renewable energy, the problem of power grid peak regulation due to excess power capacity is very prominent. However, due to the traditional "heat-based power" mode of cogeneration units, peak shaving during the heating period is particularly difficult, and the problems of wind and nuclear abandonment are very serious. Therefore, it is an urgent problem to be solved in my country's thermal power industry to realize thermoelectric decoupling and improve the flexibility of cogeneration units. The realization of thermoelectric decoupling is to meet the needs of users’ thermal load, while reducing the output power of the unit as much as possible. The problems to be solved include: (1) Increase the output thermal load of the boiler as much as possible, so as to break through the limit of the minimum stable combustion load of the boiler; (2) ) Use as much waste heat as possible in the coal-fired power generation process to supply heat to the outside, so as to improve energy utilization efficiency.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art, and provide the main steam of the coal-fired generating set to inject the low-pressure steam at the outlet of the generator through the ejector to form a heat source for driving the absorption heat pump, and the absorption heat pump simultaneously recovers part of the low-pressure cylinder of the steam turbine A thermoelectric decoupling system based on an absorption heat pump that uses the heat of the exhaust steam to supply heat to the outside.

The concrete technical scheme that the present invention adopts is as follows:

A thermoelectric decoupling system based on an absorption heat pump, including a boiler, a steam turbine high pressure cylinder, a steam turbine medium and low pressure cylinder, a condenser, a condensate pump and a heat recovery system connected in sequence, and is characterized in that it also includes an absorption heat pump, the The absorption heat pump includes a generator, a condenser, an absorber, a solution pump, a solution heat exchanger and a solution valve. The main steam outlet of the boiler communicates with the generator of the absorption heat pump through an ejector, and the low-pressure steam at the outlet of the generator Connected to the same ejector, the main steam regulating valve is installed on the pipeline connecting the main steam to the ejector, and the generator outlet low-pressure steam regulating valve is installed on the pipeline connecting the generator outlet steam to the ejector; the steam turbine The exhaust port of the medium and low pressure cylinder is connected with the absorber of the absorption heat pump through pipelines, and the absorption heat pump is used to recover the heat in the exhaust steam of the medium and low pressure cylinder of the steam turbine, thereby further improving the comprehensive energy utilization efficiency of the system; the outlet of the absorber is connected with the generation A solution pump and a solution heat exchanger are installed on the pipeline connected to the inlet of the generator; the outlet of the generator communicates with the inlet of the absorber through a pipeline passing through the solution heat exchanger and a solution valve installed on the pipeline.

Furthermore, the working fluid of the open absorption heat pump formed by connecting the generator, the condenser and the absorber is lithium bromide and water.

In addition, the water in the heating network is connected to the absorber and the condenser through pipelines in turn, so as to absorb heat in the absorber and condenser in turn and then supply heat to the outside.

Furthermore, the function of the ejector is: the main steam is used as high-pressure steam to eject the low-pressure steam from the outlet of the generator to form medium-pressure steam and enter the generator.

Another object of the present invention is to provide a kind of operation method of the thermoelectric decoupling system based on absorption heat pump, it is characterized in that: comprise the following steps:

⑴Adjust the main steam flow into the generator through the main steam regulating valve connected to the ejector inlet;

⑵Adjust the low-pressure steam flow into the generator through the generator outlet low-pressure steam regulating valve connected to the same ejector inlet.

Advantage and beneficial effect of the present invention are:

The invention comprises an open absorption heat pump composed of a generator, a condenser, an absorber, a solution pump, a solution heat exchanger and a solution valve. Due to the cancellation of steam extraction for heat supply, the present invention can realize thermoelectric decoupling and solve the problem of poor flexibility of cogeneration units in my country. The present invention uses the heat of the main steam of the boiler to supply heat to the outside, and the boiler heat load is relatively high; it can be adjusted into the absorption type The main steam flow in the heat pump realizes the adjustment of the heat absorbed by the heating surface of the boiler, which is conducive to the safe and stable operation of the boiler; injects part of the steam generated in the generator to the ejector, and increases the pressure to provide driving force for the generator. A part of high-grade steam is replaced by low-grade steam to reduce heating costs; the open absorption heat pump absorbs the exhaust heat of steam turbine to supply external heat, which improves COP.

Description of drawings

Fig. 1 is a diagram of the thermoelectric decoupling system of the present invention.

Detailed ways

The present invention is further described in detail through the following examples, but the technical content described in this example is illustrative rather than limiting, and should not limit the protection scope of the present invention accordingly.

A thermoelectric decoupling system based on an absorption heat pump, as shown in Figure 1, the innovation of the present invention is that it includes a boiler, a steam turbine high pressure cylinder, a steam turbine medium and low pressure cylinder, a condenser, a condensate pump and a heat recovery system connected in sequence , also includes an absorption heat pump, the absorption heat pump includes a generator, a condenser, an absorber, a solution pump, a solution heat exchanger and a solution valve, and the main steam outlet of the boiler is connected to the generator of the absorption heat pump through an ejector The low-pressure steam at the outlet of the generator is connected to the same ejector, the main steam regulating valve is installed on the pipeline connecting the main steam to the ejector, and the generator outlet is installed on the pipeline connecting the steam at the outlet of the generator to the ejector Low-pressure steam regulating valve; the exhaust port of the middle and low pressure cylinder of the steam turbine is connected with the absorber of the absorption heat pump through a pipeline, and the heat in the exhaust steam of the middle and low pressure cylinder of the steam turbine is recovered by the absorption heat pump, thereby further improving the comprehensive energy utilization of the system Efficiency; a solution pump and a solution heat exchanger are installed on the pipeline connecting the outlet of the absorber with the inlet of the generator; the outlet of the generator passes through the pipeline passing through the solution heat exchanger and the solution valve installed on the pipeline and absorb connected to the inlet of the device.

In this embodiment, the working fluids of the open absorption heat pump formed by connecting the generator, the condenser and the absorber are lithium bromide and water. The heating network water is connected to the absorber and the condenser through the pipeline in turn, so that heat is supplied to the outside after absorbing heat in the absorber and condenser in turn. The function of the ejector is: the main steam is used as high-pressure steam to eject the low-pressure steam from the outlet of the generator to form medium-pressure steam and enter the generator.

The operation method of the above-mentioned thermoelectric decoupling system based on the absorption heat pump includes the following steps:

⑴Adjust the main steam flow into the generator through the main steam regulating valve connected to the ejector inlet;

⑵Adjust the low-pressure steam flow into the generator through the generator outlet low-pressure steam regulating valve connected to the same ejector inlet.

Example

As shown in Figure 1, the present invention is a thermoelectric decoupling system, which includes a boiler 1, a steam turbine high-pressure cylinder 2, a steam turbine medium-low pressure cylinder 3, a condenser 5, a condensate pump 6 and a heat recovery system 7 connected in sequence. It is characterized in that: it also includes a generator 44, a condenser 45, an absorber 46, a solution pump 47, a solution heat exchanger 49 and a solution valve 48 connected to form an open absorption heat pump; the main steam outlet of the boiler 1 passes through the injection The generator 42 is connected with the generator 44 of the absorption heat pump, and the low-pressure steam at the outlet of the generator 44 is connected to the same ejector 42, and the main steam regulating valve 41 is installed on the pipeline connecting the main steam to the ejector 42, and the generator The outlet steam is connected to the pipeline of the ejector 42, and the generator outlet low-pressure steam regulating valve 43 is installed; the exhaust port of the middle and low pressure cylinder 3 of the steam turbine is connected with the absorber 46 of the absorption heat pump through the pipeline, and the absorption heat pump is used to Recover the heat in the exhaust steam of the middle and low pressure cylinder 3 of the steam turbine, thereby further improving the comprehensive energy utilization efficiency of the system; a solution pump 47 and a solution heat exchanger 49 are installed on the pipeline connected between the outlet of the absorber 46 and the inlet of the generator 44; The outlet of the generator 44 communicates with the inlet of the absorber 46 through a pipeline passing through a solution heat exchanger 49 and a solution valve 48 installed on the pipeline.

The generator 44, the condenser 45 and the absorber 46 are connected to form an open absorption heat pump. The working fluid is lithium bromide and water. The absorption heat pump utilizes steam heat to drive the circulation of the working fluid.

The hot network water is connected to the absorber 46 and the condenser 45 sequentially through pipelines, thereby supplying heat to the outside after absorbing heat in the absorber 46 and the condenser 45 in turn.

As shown in Figure 1, the operation method of the thermoelectric decoupling system of the present invention, the operation method of the thermoelectric decoupling system, the main steam flow rate entering the generator 44 is controlled by the main steam regulating valve 41 connected to the inlet of the ejector 42 To adjust, the low-pressure steam flow rate entering the generator 44 is adjusted through the low-pressure steam regulating valve 43 at the outlet of the generator 44 connected to the inlet of the same ejector 42. The function of the ejector 42 is: the main steam is ejected as high-pressure steam The low-pressure steam from the outlet of the generator 44 forms medium-pressure steam and enters the generator.

The steam ejector can use the heat of the high-pressure steam to recover the heat of the low-pressure steam at the outlet of the low-grade generator, so as to improve the energy utilization efficiency.

Taking a 300MW heat extraction unit as an example, the main steam parameter is 16.7MPa/538°C, the reheat steam parameter is 3.23MPa/538°C, the rated back pressure is 5.2kPa, and the rated heating extraction pressure is 0.3MPa.

When the heat supply is 300MW, the electric load adjustment range of the original unit under this heat supply is [238.38MW, 297.42MW]. After adopting this technology, the electric load adjustment range is expanded to [188.134MW, 321.35MW] ].

After the transformation of the absorption heat pump, the safe operating range of the unit has been expanded, which can significantly improve the ability of the heating unit to increase and decrease the electric load.

Claims (5)

1. The utility model provides a thermoelectric decoupling zero system based on absorption heat pump, is including boiler, steam turbine high pressure cylinder, the steam turbine low pressure cylinder that are linked together in proper order, condenser, condensate pump and backheat system, its characterized in that: the absorption heat pump comprises a generator, a condenser, an absorber, a solution pump, a solution heat exchanger and a solution valve, wherein a main steam outlet of the boiler is communicated with the generator of the absorption heat pump through an ejector, low-pressure steam at the outlet of the generator is connected to the same ejector, a main steam regulating valve is installed on a pipeline through which the main steam is communicated with the ejector, and a generator outlet low-pressure steam regulating valve is installed on a pipeline through which the steam at the outlet of the generator is communicated with the ejector; the exhaust port of the low-pressure cylinder in the steam turbine is communicated with an absorber of the absorption heat pump through a pipeline, and the heat in the exhaust of the low-pressure cylinder in the steam turbine is recovered by the absorption heat pump, so that the comprehensive energy utilization efficiency of the system is further improved; a solution pump and a solution heat exchanger are arranged on a pipeline which is communicated with the outlet of the absorber and the inlet of the generator; the outlet of the generator is communicated with the inlet of the absorber through a pipeline passing through the solution heat exchanger and a solution valve arranged on the pipeline.

2. the system of claim 1, wherein the system further comprises a heat pump coupled to the first heat source and configured to: the generator, the condenser and the absorber are communicated to form an open absorption heat pump, and the working medium of the open absorption heat pump is lithium bromide and water.

3. The system of claim 2, wherein the system further comprises a heat pump coupled to the first heat exchanger and a heat pump coupled to the second heat exchanger, wherein the system further comprises: the heat supply network water is communicated with the absorber and the condenser through pipelines in sequence, so that heat is absorbed in the absorber and the condenser in sequence and then heat is supplied to the outside.

4. a decoupling system based on absorption heat pump according to claim 1 or 2 or 3, wherein: the ejector has the following functions: the main steam is used as high-pressure steam to inject low-pressure steam from the outlet of the generator to form medium-pressure steam, and the medium-pressure steam enters the generator.

5. The method of operating an absorption heat pump based thermoelectric decoupling system according to claim 4, wherein: the method comprises the following steps:

The method comprises the steps that the main steam flow entering a generator is adjusted through a main steam adjusting valve connected with an inlet of an ejector;

The low-pressure steam flow entering the generator is adjusted through a generator outlet low-pressure steam adjusting valve connected with the same ejector inlet.